The majority of OS X apps are self-updating; no need for a central repository. (The iPhone and iPad GUI has different priorities and requirements, so there's little point wasting bytes arguing about the App Store.)
Ultimately, the problem isn't the endless stream of security patches. It's the willingness of the users to accept the shoddy coding that *causes* these patches to be produced in the first place.
It's the 21st Century, but we still accept EULAs that effectively absolve *all* developers—and no, it's not just Microsoft; the GNU / Linux fanboys are just as guilty—of any consequences of responsibility for their code's actions. If you are unwilling to trust your *own* code to do what you claim it does, why the hell are you even wasting time writing it?
(And yes, it IS fucking possible to write code to a much higher standard of quality. Check out SparkADA sometime. Or do you think Boeing and Airbus aircraft pop up dialogs in mid-flight informing the crew that a new service pack is available for download?)
Quit adding features. Start adding *stability*.
(Oh, and if your users are "randomly clicking" on stuff, as some have suggested, perhaps you could explain why that action is causing harm to their computer? Perhaps some education in the field of user experience and interaction design is advisable. For you.)